Ok here we go. Recently I had to rebuild my engine again do to installation problems, pinched a coolant seal upon reassembly. After the rebuild my car started lurching hardcore on every shift and during regular driving. So my Dad rebuild it and now my car has a mad vibration going. Over 70mph it is very very noticable because it shakes my car. Now I've read that U-joints are a likely problem, but I thought it might be something else considering it just started happening after the rebuild.

BTW- Could it be the diff mount? I have it ghetto rigged with extra rubber and other stuff, but I dont think that is the problem, but Im not for sure.

Any ideas? Thanks

 

If the car started lurching, like the tranny or back end was moving up and down too much when it shouldn't have. This would definately cause stress on the u-joints on the driveshaft.

I know this because my 4X4 was rocking back and fourth for a while. As rocked back and fourth while the drive shaft was spinning, it was pulling on the u-joints.

You can picture the drive shaft that is supposed to go only up and down to a certain degree. But if it goes too far for too long its as if the U-joint acts as a motor or tranny mount to stabilize the motion. So the U-joints end up taking on the extra slack that some other mount in the drivetrain didn't = Damage.

 

Thanks man, youre very helpful. Im going to go find a new driveshaft.

 

Might not need a new drive shaft unless its bent. Maybe Just some new U joints.

You can get those at checker....Actually I'd get em at napa or Big A really. Been having bad experiences with checker/autozone parts lately. They're like the walmart of the autoparts industry.

If you get new U joints, you can have your local shop press them in for you.

And also keep in mind that if you don't solve the rocking problem, the U joints will blow again.